A novel human B lymphotropic virus (HBLV) has been isolated recently from patients with lymphoproliferative disorders. This herpes-like virus has been shown to specifically infect only B lymphocytes and alter both their morphology and growth characteristics. The significance of the virus in causing human disease has not been fully evaluated yet, but is of much interest to researchers and clinicians. This applicant proposes to develop non-radioactive DNA probes to HBLV. The probes will be tested on HBLV infected cord blood cells using both a slot blot and an in situ hybridization approach. Eventually a simplified DNA detection system will be developed with all of the necessary components supplied in a kit form for routine use in clinical laboratories. The availability of such an inexpensive simple to use DNA probe kit for HBLV will greatly facilitate the study of the etiological and epidemiological significance of the virus. The objective is to develop non-radioactive DNA probes for human B lymphotropic virus that can be used for routine clinical diagnosis of blood specimens. Specific objectives of phase I are to subclone sequences which specifically hybridize to HBLV into M13 vectors and use them to prepare non-radioactive DNA probes; to test DNA probes on extracts of HBLV infected cultured cells using the slot blot hybridization procedure; to test DNA probes on HBLV infected cells fixed on slides by in situ hybridization; and to develop simplified procedures for sample handling and hybridization for both the slot blot and in situ hybridization formats. The results of these phase I studies will be used as a basis for developing simplified diagnostic tests for screening actual patient samples during phase II.